1Electrode is used, and the contact area with water is large, and the measurement result is reliable and accurate. 2Electrode of the water quality tester is designed to be detachable, which is faster and more convenient. 3Drinking hydrogen rich water for a long time can effectively remove the free radicals in the body, which can help sleep and improve the skin. 4LCD high definition display with backlight function can easily cope with the night environment. 50~50 automatic temperature compensation automatically eliminates measurement errors according to changes in ambient temperature. Item Type: DissolveHydrogenMeter Material: ABS Size: Approx. 20.7 x 3.6 x 3.2cm / 8.2 x 1.4 x 1.3in Weight: Approx. 156g / 5.5oz Range: ppb: 0-1999ppb / ppm: 0-1.99ppm Resolution: ppb: 1ppb / ppm: 0.01ppm Accuracy: ppb: 10ppb / ppm: 0.02ppm Automatic Temperature Compensation: 0~50 Battery Information: 2 x AAA Battery 1.5V(Battery Not Included) Working Temperature: 0~50 1 xDissolveHydrogenMeter 1 x User Manual